Charlie Chaplin’s fourth wife Oona, with whom he had eight children, was the daughter of which American writer?

Oona Chaplin, Lady Chaplin (14 May 1925 – 27 September 1991) was the daughter of Nobel and Pulitzer-Prize-winning Irish-American playwright Eugene O'Neill and English-born writer Agnes Boulton, and the 4th and last wife of English actor and filmmaker Charlie Chaplin (16 April 1889 – 25 December 1977).

O'Neill's parents divorced in 1929 when she was four, largely due to Eugene O'Neill's alcoholism and marital infidelities. She was then raised by her mother in Point Pleasant, New Jersey. Thereafter, she rarely saw her father.

Eugene Gladstone O'Neill (October 16, 1888 – November 27, 1953) as a playwright was amongst the first to introduce into U.S. drama techniques of realism, earlier associated with Russian, Swedish and Norwegian playwrights Chekhov, Ibsen, and Strindberg. The drama "Long Day's Journey into Night" is often numbered on the short list of the finest U.S. plays in the 20th century, alongside Tennessee Williams's "A Streetcar Named Desire" and Arthur Miller's "Death of a Salesman". With few exceptions, O'Neill's plays involve some degree of tragedy and personal pessimism. O'Neill wrote 31 full length plays and a further 17 one-act plays

When Charlie Chaplin married Oona O’Neill in June 1943, he was 53 and she was 18. They met when Charlie Chaplin considered her for a part in an unmade film, "Shadow and Substance" (during 1942). Together Oona and Charlie Chaplin had 8 children (Geraldine, Michael, Josephine, Victoria, Eugene, Jane, Annette and Christopher).